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Comment by woah | Hacker News Reader

The backend stuff described here is relatively trivial. You could just do everything on a blockchain, at the expense of poor scalability if it actually took off and the eternal reproach of HN.

The thing that is very hard to replicate is that Uber provides a form of insurance and moderation, where human operators can choose to refund for cancelled rides in situations where it is tricky to determine who is at fault.

They are also able to do it optimistically, refunding people and then adjusting policies if it turns out the policies are being abused. This stuff is very hard to encode into a decentralized protocol.

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> They are also able to do it optimistically, refunding people and then adjusting policies if it turns out the policies are being abused. This stuff is very hard to encode into a decentralized protocol.

Whats the nexus between centralization and ability to refund? Regardless of centralization i can cancel my credit card to stop you from clawing back an optimistic refund, regardless of centralization the protocol could force a waiting period before withdrawing optimistically refunded monies, etc.

There's any number of ways to solve the problem of refunds. Escrow contracts come to mind. The only question is what kind of rules/mediation we'd want to implement.

At the risk of further HN reproach,

You're exactly right --and there are some ways to solve the problem while remaining decentralized.

The ideas you bring up are, essentially: credit, insurance, risk, reputation.

Tracking reputation on-chain is workable, and already exists. For instance, some airdrops have been done based on on-chain activity and reputation. Decentralized founders wanted to reward those with "good on-chain behavior."

The way I imagine this would work for a decentralized Uber:

  - Pay for fares on-chain (ideally, a 2nd or 3rd layer, e.g. a ZK rollup)
  - Drivers rate users on-chain, using the payment address
  - Possibly use other on-chain information to form a "credit/reputation profile"

It's possible this entire idea of reputation/credit could be packaged into a dedicated protocol that could be referenced by any number of other on-chain systems (such as this decentralized uber). There are some projects along these lines in existence, I believe, but none have gotten traction yet, and are mostly focused around lending.

To protect privacy, we'd need to take extra care to shield user info (using e.g. ZK proofs), or just make everything completely transparent. It's also possible to use privacy for the payments/assets system, and make the reputation system transparent.

I do not think we'd want to be storing ride data, etc. on-chain. I'd look into something like OrbitDB, or some other decentralized system that's meant to be a database.

How would a blockchain ride-hailing system work for women - would it expect people to jump into any car with a driver who claims to own blockchain address X (with ratings from other addresses)?

The world looks quite different when a significant proportion of the population are significantly stronger than you - strong enough that you couldn't physically stop them doing horrible things to you.

Uber with random drivers is sketchy, but you know there's been at least minimal background checks, and knowing that Uber are tracking the ride gives a bit more safety.

The current system expects people to jump into any car with a driver who claims to be the registered driver of said car.

> who claims to own blockchain address X

Ownership of a blockchain address can be proven with a signature.

In the current system, I've never had a taxi driver prove they are the person registered to drive that particular taxi.

> Ownership of a blockchain address can be proven with a signature.

How? If my friend gives me their passcode / phone / Token, I can impersonate them.

Maybe this is ok. The reputation of the account is still at stake and the friend may have trusted you with their private keys so that you can give taxi rides and increase the overall account reputation.

If the private keys were stolen then a malicious person could impersonate your friend and act badly. Similarly, in the current system, a person can pretend to be a taxi driver and act badly.

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